* {
    margin: 0;
    padding: 0;
    list-style: none;
    box-sizing: border-box;
    font-weight: bold;
}

.wrap {
    width: 900px;
    margin: auto;
}

.box img {
    width: 300px;
    height: 300px;
    float: left;
}

.box::after {
    content: "";
    clear: both;
    display: block;
}

.mask {
    width: 100%;
    height: 100%;
    position: fixed;
    left: 0;
    top: 0;
    background: rgba(0, 0, 0, 0.7);
}

.content {
    left: 50%;
    top: 50%;
    position: fixed;
    transform: translate(-50%, -50%);
    padding: 40px;
    background: #fff;
    border-radius: 30px;
}

.content b {
    float: right;
    margin-right: -15px;
    margin-top: -35px;
    font-size: 26px;
}

.content .bigImg {
    width: 600px;
    height: 500px;
}
.content .left {
    left: 0;
    top: 50%;
    transform: translate(0, -50%);
    position: fixed;
    font-size: 36px;
}

.content .right {
    right: 0;
    top: 50%;
    transform: translate(0, -50%);
    position: fixed;
    font-size: 36px;
}

.content ul {
    text-align: center;
}
.content ul li {
    width: 50px;
    height: 50px;
    display: inline-block;
    opacity: 0.3;
}

.content ul li.active {
    border: 2px red solid;
    opacity: 1;
}

.content ul li img {
    width: 100%;
    height: 100%;
}
